Dementia and cognitive impairment are major public health problems affecting a wide variety of populations groups within the United States and worldwide. The rapid increase of Mexican Americans in the US offers a unique opportunity to study the causes of and incidence of dementia in an important non-European population with significant cerebrovascular and metabolic disease. The Sacramento Area Latino Study on Aging is an representative, population-based, cohort study of nearly 1800 community-dwelling Latinos, primarily Mexican-Americans, aged 60 and over in 1998-99. This cohort has been followed for 2.5 years from baseline. Dementia prevalence and two-year incidence has been ascertained through a multi-step process of screening and clinical examination that has a high level of sensitivity. The first phase of the study was oriented towards the study of cognitive status and dementia in older Mexican Americans. Our primary goal has been to estimate dementia prevalence and to identify pathways and modifying factors that influence the occurrence of dementia in this unique cohort. Type 2 diabetes (32%) and depressive symptoms (25%) are high in this cohort. A low prevalence of the E4 allele may point to a smaller genetic contribution by this genotype to the risk of dementia. Innovative measures of cultural orientation and immigration have been obtained. We find these are important predictors of diabetes, stroke, cognitive impairment, dementia and depression. The renewal will focus on (a) more precisely estimating dementia-free 'survival time' and comparing this in participants with and without type 2 diabetes or stroke, (b) in those who are cognitively impaired but do not meet criteria for dementia, describing the trajectory of cognitive and functioning decline and identifying predictors of this decline and (c) evaluating the role of depressive symptoms and depression in the development of dementia and cognitive impairment. This study provides a highly appropriate model in which to study the influence of sociocultural and vascular risk factors on cognitive impairment, depression and dementia in a unique, understudied and at-risk population.